[PyQt] How to call DBus method with UInt32 arg?

[Evade Flow]

Hi, all. Does anyone have experience trying to pass UInt32 arguments to
a DBus service using PyQt4.QtDBus?  The program appended below generates
the following error:

% python build_connection.py 0 0 0 1234
Call failed: No such method 'buildConnection' in interface
'com.acme.Audio.Connection' at object path
'/com/acme/Audio/Connection' (signature '(i)(i)(i)i')

I think it's failing because the actual signature of the method to be
called is '(i)(i)(i)u' [??] (Don't ask why the designers of this
interface wrapped a DBus struct around every int--I have no idea. `:-@)

Can anyone confirm whether passing unsigned 32-bit arguments is possible
with my version of PyQt4/SIP:


>>> import PyQt4.QtCore
>>> PyQt4.QtCore.PYQT_VERSION_STR
'4.9.3'
>>> PyQt4.QtCore.PYQT_VERSION
264451
>>> import sip
>>> sip.SIP_VERSION_STR
'4.13.3'
>>> sip.SIP_VERSION
265475

Is there some way I can coerce the last arg to the right type?


--------------------

#!/usr/bin/env python

from PyQt4 import QtDBus
from PyQt4.QtCore import QCoreApplication

if __name__ == '__main__':
    import sys
    from os.path import basename

    if len(sys.argv) != 5:
        print("Usage: %s <sender> <source> <sink> <connID>" %
            (basename(sys.argv[0]),))
        sys.exit(1)

    sender = int(sys.argv[1])
    source = int(sys.argv[2])
    sink = int(sys.argv[3])
    conn_id = int(sys.argv[4])

    app = QCoreApplication(sys.argv)

    bus = QtDBus.QDBusConnection.connectToBus(
        "tcp:host=192.168.0.1,port=6668",
        "myConnection"
    )

    iface = QtDBus.QDBusInterface(
        'com.acme.Audio',
        '/com/acme/Audio/Connection',
        'com.acme.Audio.Connection',
        bus
    )

    if not iface.isValid():
        sys.stderr.write("Invalid interface: %s\n" % bus.lastError().message())
        sys.exit(1)

    sender_ = QtDBus.QDBusArgument()
    sender_.beginStructure()
    sender_.add(sender)
    sender_.endStructure()

    source_ = QtDBus.QDBusArgument()
    source_.beginStructure()
    source_.add(source)
    source_.endStructure()

    sink_ = QtDBus.QDBusArgument()
    sink_.beginStructure()
    sink_.add(sink)
    sink_.endStructure()

    msg = iface.call('buildConnection', sender_, source_, sink_, conn_id)
    reply = QtDBus.QDBusReply(msg)

    if not reply.isValid():
        sys.stderr.write("Call failed: %s\n" % reply.error().message())
        sys.exit(1)

    #else:
        #sys.stdout.write("Reply was: %s\n" % reply.value())